UniBall Signo Bit 0.18mm Pen

This is the world's thinnest pen, with the tip measuring in at an amazing 0.18mm and resulting in a line as thin as 0.13mm. The pen tip is small enough to write on a single grain of rice, in case there were any doubts as to the absolute thinness of this pen.

This is a ball pen that uses Uni-Ball's exceptional waterproof and fadeproof ink. Although the tip might be too small for some to accurately identify the differences in color, the Bit comes in an excellent variety for those keen eyes including: orange, light blue, violet, pink, emerald and the standard red, black and blue.

These pens are not for the faint of heart as they require intense precision (to prevent skipping) and a light hand to prevent breaking the tip. The writing surface must also be high quality like cotton or a high bond paper. However, for calligraphers and artists, you won't find a smaller tip.